The long-term objective of this project is to demonstrate the usefulness and hence the need to establish a center for Mossbauer spectroscopy in biological materials. Our immediate aim is to show that the Mossbauer effect is sensitive to modifications and conformational changes in a protein which occur rather remotely from the active site. It is normally assumed that the Mossbauer effect measures only the local environment of the Mossbauer nucleus. The determination that the Mossbauer effect can detect remote modifications and conformational differences will establish the technique as an extremely important one for biological applications. To be specific, we plan to study enriched (in 57Fe) samples of human mutant hemoglobins. There are now over 400 such mutants. The point mutations in these abnormal hemoglobins occur at different distances from the heme. In addition, the electrical nature of the mutations vary as well as their interactions with other residues in the polypeptide chain. Thus, human mutant hemoglobins present an ideal system in which to study the range and sensitivity of iron Mossbauer spectroscopy in biological material. We also will study samples of enriched HbO2 and deoxyhemoglobin, separated alpha and beta chains, and the reconstituted tetramer. The samples will be examined using transmission Mossbauer spectroscopy in our He3/He4 dilution refrigerator from a temperature of 77K down to a temperature of 60mK in the presence of an applied magnetic field of up to 5 Teslas. Analysis of the results will be made using our theoretical computer programs which include the possible determination of dynamic effects. Such molecular dynamic effects, if observed, may prove to be the key for understanding important biological processes such as conformational changes. In general, positive results from this project will suggest further Mossbauer studies of biological relevance.